J2K: Get nullability from variable initializer when converting call

#KT-11534 In Progress

j2k/testData/fileOrElement/nullability/notNullCast.kt

@@ -1,5 +1,3 @@
-// ERROR: Type mismatch: inferred type is Passenger.PassChild? but Passenger.PassChild was expected
-// ERROR: Type mismatch: inferred type is Passenger.PassChild? but Passenger.PassChild was expected
 class Passenger {
     open class PassParent
 
@@ -18,9 +16,9 @@ class Passenger {
         val pass = provideNullable(1)
         if (1 == 2) {
             assert(pass != null)
-            accept2(pass as PassChild?)
+            accept2((pass as PassChild?)!!)
         }
-        accept2(pass as PassChild?)
+        accept2((pass as PassChild?)!!)
     }
 
     fun accept1(p: PassChild) {

j2k/testData/fileOrElement/nullability/nullableInitializer1.java

@@ -0,0 +1,24 @@
+import org.jetbrains.annotations.Nullable;
+
+public class Test {
+    public String nullableString(int p) {
+        return p > 0 ? "response" : null;
+    }
+
+    private String nullableInitializerField = nullableString(3);
+    private String nullableInitializerFieldFinal = nullableString(3);
+    public String nullableInitializerPublicField = nullableString(3);
+
+    public void testProperty() {
+        nullableInitializerField = "aaa"
+
+        nullableInitializerField.charAt(0);
+        nullableInitializerFieldFinal.charAt(0);
+        nullableInitializerPublicField.charAt(0);
+    }
+
+    public void testLocalVariable() {
+        String nullableInitializerVal = nullableString(3);
+        nullableInitializerVal.charAt(0);
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer1.kt

@@ -0,0 +1,24 @@
+// ERROR: Type mismatch: inferred type is String? but String was expected
+// ERROR: Type mismatch: inferred type is String? but String was expected
+class Test {
+    fun nullableString(p: Int): String? {
+        return if (p > 0) "response" else null
+    }
+
+    private var nullableInitializerField: String = nullableString(3)
+    private val nullableInitializerFieldFinal = nullableString(3)
+    var nullableInitializerPublicField: String = nullableString(3)
+
+    fun testProperty() {
+        nullableInitializerField = "aaa"
+
+        nullableInitializerField[0]
+        nullableInitializerFieldFinal!![0]
+        nullableInitializerPublicField[0]
+    }
+
+    fun testLocalVariable() {
+        val nullableInitializerVal = nullableString(3)
+        nullableInitializerVal!![0]
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer2.java

@@ -0,0 +1,21 @@
+import org.jetbrains.annotations.Nullable;
+
+public class TestJava {
+    public Object nullableObj(int p) {
+        return p > 0 ? "response" : null;
+    }
+
+    public String nullableInitializerFieldCast = (String) nullableObj(3);
+    private String nullableInitializerPrivateFieldCast = (String) nullableObj(3);
+
+    public void testProperty() {
+        nullableInitializerFieldCast.charAt(0);
+        nullableInitializerPrivateFieldCast.charAt(0);
+    }
+
+    public void testLocalVariable() {
+        String nullableInitializerValCast = (String) nullableObj(3);
+
+        nullableInitializerValCast.charAt(0);
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer2.kt

@@ -0,0 +1,20 @@
+// ERROR: Type mismatch: inferred type is String? but String was expected
+class TestJava {
+    fun nullableObj(p: Int): Any? {
+        return if (p > 0) "response" else null
+    }
+
+    var nullableInitializerFieldCast: String = nullableObj(3) as String?
+    private val nullableInitializerPrivateFieldCast = nullableObj(3) as String?
+
+    fun testProperty() {
+        nullableInitializerFieldCast[0]
+        nullableInitializerPrivateFieldCast!![0]
+    }
+
+    fun testLocalVariable() {
+        val nullableInitializerValCast = nullableObj(3) as String?
+
+        nullableInitializerValCast!![0]
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer3.java

@@ -0,0 +1,20 @@
+import org.jetbrains.annotations.Nullable;
+
+public class Test {
+    public String notNullString(int p) {
+        return "response";
+    }
+
+    private String notNullInitializerField = notNullString(3);
+    public String notNullInitializerPublicField = notNullString(3);
+
+    public void testProperty() {
+        notNullInitializerField.charAt(0);
+        notNullInitializerPublicField.charAt(0);
+    }
+
+    public void testLocalVariable() {
+        String notNullInitializerVal = notNullString(3);
+        notNullInitializerVal.charAt(0);
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer3.kt

@@ -0,0 +1,18 @@
+class Test {
+    fun notNullString(p: Int): String {
+        return "response"
+    }
+
+    private val notNullInitializerField = notNullString(3)
+    var notNullInitializerPublicField = notNullString(3)
+
+    fun testProperty() {
+        notNullInitializerField[0]
+        notNullInitializerPublicField[0]
+    }
+
+    fun testLocalVariable() {
+        val notNullInitializerVal = notNullString(3)
+        notNullInitializerVal[0]
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer4.java

@@ -0,0 +1,26 @@
+import org.jetbrains.annotations.Nullable;
+
+public class TestJava {
+    private String notNullInitializerFieldNullableUsage = "aaa";
+    private String notNullInitializerFieldNotNullUsage = "aaa";
+
+    private String nullInitializerFieldNullableUsage = null;
+    private String nullInitializerFieldNotNullUsage = null;
+
+    public void testNotNull(@Nullable Object obj) {
+        if (true) {
+            notNullInitializerFieldNullableUsage = (String) obj;
+            notNullInitializerFieldNotNullUsage = "str";
+
+            notNullInitializerFieldNullableUsage.charAt(1);
+            notNullInitializerFieldNotNullUsage.charAt(1);
+        }
+        else {
+            nullInitializerFieldNullableUsage = (String) obj;
+            nullInitializerFieldNotNullUsage = "str";
+
+            nullInitializerFieldNullableUsage.charAt(1);
+            nullInitializerFieldNotNullUsage.charAt(1);
+        }
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer4.kt

@@ -0,0 +1,24 @@
+// ERROR: Type mismatch: inferred type is String? but String was expected
+class TestJava {
+    private var notNullInitializerFieldNullableUsage = "aaa"
+    private var notNullInitializerFieldNotNullUsage = "aaa"
+
+    private var nullInitializerFieldNullableUsage: String? = null
+    private var nullInitializerFieldNotNullUsage: String? = null
+
+    fun testNotNull(obj: Any?) {
+        if (true) {
+            notNullInitializerFieldNullableUsage = obj as String?
+            notNullInitializerFieldNotNullUsage = "str"
+
+            notNullInitializerFieldNullableUsage[1]
+            notNullInitializerFieldNotNullUsage[1]
+        } else {
+            nullInitializerFieldNullableUsage = obj as String?
+            nullInitializerFieldNotNullUsage = "str"
+
+            nullInitializerFieldNullableUsage!![1]
+            nullInitializerFieldNotNullUsage!![1]
+        }
+    }
+}